Interviews of 545 expected cases of histologically confirmed adenocarcinomas of the Colon & Rectum diagnosed in Puerto Rico from Jan., 1973 to Dec., 1974, and of 1540 age-sex matched controls from the same community as the patient and that had lived there for at least 10 years. Cancer cases will be obtained from biopsy reports of adenocarcinomas of Colon & Rectum sent regularly to the Central Cancer Registry. Interviews will be performed by independent interviewers. If the patient or control died or was physically or mentally incapacitated, a member of the family who has lived for no less than 10 years with the patient or control will be interviewed. Questionnaire will include questions related with religion, birthplace, places of residence, occupation and uses of alcohol and Tobacco. There will be also querries about: Dietary patterns (amount, type and frequency of: unabsorbable fiber, refined carbohydrates, meats, other protein foods, vitamins, etc.); Medicine and procedures to correct constipation (type, frequency, amount & time); Previous large intestine organic and functional diseases (Polyps, ulcerative colitis, diverticular diseases, histozomiasis, hemorroids, etc.); Other previous digestive diseases; Genetic patterns of cancer of the Colon and Rectum among the first degree relatives. The 1,090 interviews will be punched and tabulated. Matched-chi- square tests will be used to determine statistical significance for differences between cases and controls. The conventional method for relative risk calculation will be used. Some of the findings of this study will be compared with those obtained in a nutritional pattern study to be conducted in the New York City by the Dept. of Community and Preventive Medicine of the New York Medical College, among Puerto Ricans living in New York and who developed cancer of the large intestine.